Dianella: planting, cultivation and maintenance

botany

Dianella are rhizomatous perennials comprising around forty species, about half of which are native to Australia. The others originate from New Zealand, eastern Africa, Madagascar, Southeast Asia, and the Pacific Islands. They primarily grow in woodlands, as well as in scrublands and heathlands. The most commonly cultivated species are Dianella revoluta and Dianella tasmanica, native to Australia and Tasmania. There are also numerous varieties, prized for their foliage in various shades.

Dianella ensifolia: Botanical illustration

Dianella belongs to the botanical family Xanthorrhoeaceae. This family includes ornamental plants with a very exotic style, such as Kniphofias, Daylilies, Eremurus, Aloes, Phormiums, Asphodels, Bulbines, and Haworthias.

Dianella was named after the Roman goddess Diana. The suffix ella means “small.” The species name Dianella tasmanica refers to its geographical origin: Tasmania. As for Dianella caerulea, its species name means “blue,” alluding to the flowers and berries.

Dianella forms clumps of broad, slender leaves, resembling those of Irises. They reach between 40 and 80 cm in height, or even up to 1.20 m. Smaller varieties create a stunning effect when planted en masse. Dianella has an underground rootstock, allowing the clumps to gradually expand.

The flowering of Dianella (photos: Adobe Stock / David Francis 34 / Louise Docker)

Dianella blooms in late spring or summer, between May-June and August, depending on the species. They then display loose, airy panicles, branched and 40 to 60 cm long. These bear small, star-shaped blue flowers with yellow stamens. The flowers measure 1 to 2 cm in diameter and consist of three petals and three blue sepals, all identical in appearance (referred to as tepals). They feature six yellow stamens at the center, equally decorative, along with a central pistil. The blue petals curve backward, opposite the stamens. The delicacy and lightness of the flowers create a beautiful contrast with the massive, stiff, and linear foliage. Dianella flowers are pollinated by insects, which carry pollen from the stamens to the pistils, enabling the plant to reproduce.

Dianella boasts highly graphic foliage. It consists of long, ribbon-like, upright leaves resembling those of Phormiums. The leaves are broad and stiff, with rough-edged laminae. They measure between 50 cm and 1.20 m in length and have a prominent central vein parallel to the leaf edge. Depending on the variety, the leaves can be stiff and upright (as in Dianella ‘Little Rev’) or very flexible and arched, as in Dianella ‘Emerald Arch’ or ‘Blaze’. The leaves are evergreen, ensuring year-round presence in the garden, even in winter.

The foliage of Dianella ‘Breeze’, Dianella tasmanica var. variegata, and Dianella tasmanica (photos: Jason Baker / David J. Stang / Daderot)

Dianella leaves come in a wide range of shades depending on the variety. For example, the Dianella tasmanica ‘Variegata’ features beautiful white-variegated foliage, very luminous. Conversely, the Dianella tasmanica ‘Blaze’ offers very dark, chocolate-brown foliage. Dianella ‘Cassa Blue’ has bluish leaves, while those of Dianella ‘Tas Red’ are bicolored: red at the base and green on the rest of the lamina. Dianella tasmanica ‘Rainbow’ is one of the most colorful: the leaves are green variegated with cream-yellow and tinged red at the base. ‘Rainbow Twist’, on the other hand, has gray-blue leaves edged with red-pink, with hues changing with the seasons.

Dianella is among the few perennials with decorative berries. In autumn, the flowers give way to ovoid dark blue to violet berries, shiny and measuring 1 to 1.5 cm in diameter. They contain black seeds, which can be collected to propagate the plant by sowing.

The blue-violet berries of Dianella (photo: Adobe Stock)

The main varieties of Dianella

The Most Popular Varieties

Our Favourite Varieties

Dianella revoluta Little Rev

This is a compact variety, forming small clumps of stiff, upright leaves in a blue-grey-green hue. It resembles a grass but lights up in summer with numerous small blue flowers. It looks best when planted en masse.

• Flowering time July to September
• Height at maturity 40 cm

See the product sheet

Dianella revoluta Coolvista

This variety forms clumps of fine, upright leaves in a beautiful blue-grey colour. It will easily find its place in a garden with a graphic and contemporary style.

• Flowering time July to September
• Height at maturity 60 cm

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Dianella tasmanica Variegata

A larger variety than the previous ones, also distinguished by its bright white-variegated green foliage. The leaves are arched, trailing at the tips.

• Flowering time June, July
• Height at maturity 80 cm

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Dianella tasmanica Blaze

An original variety with chocolate-brown foliage, forming small, soft, and arched clumps that beautifully highlight and contrast with its blue flowering.

• Flowering time June to August
• Height at maturity 45 cm

See the product sheet

Dianella tasmanica

This is the botanical species, as found in the wild. It bears long, bright green leaves and also produces beautiful star-shaped blue flowers with yellow stamens, followed by blue-purple berries.

• Flowering time June, July
• Height at maturity 80 cm

See the product sheet

Planting

Where to Plant?

In the warm regions of southern France, particularly on the Mediterranean coast, we recommend planting the Dianella in shade or partial shade. In Australia, in its natural habitat, it typically grows in woodland understorey and therefore appreciates shaded locations. Intense sunlight could damage its foliage. However, in the northern half of France, where temperatures are cooler, we advise planting it in full sun as it requires warmth. In any case, choose a location sheltered from cold winds. The Dianella is not a very hardy plant (though it seems to tolerate temperatures as low as –12°C in sheltered, well-drained conditions): outside the Atlantic coast and the Mediterranean basin, it will need winter protection: either by wrapping it in winter fleece and applying a thick layer of mulch around the clump, or by growing it in a pot and bringing it indoors for the winter.

Dianella is particularly well-suited to coastal gardens, as it tolerates sea spray well.

As for the soil type, the most important factor is to grow Dianella in perfectly drained soil, as stagnant moisture could cause its roots to rot. If your soil tends to retain water, improve drainage by mixing gravel or coarse sand into the planting soil. You can also plant it on a mound to ensure quick water runoff. Dianella also thrives in fertile, humus-rich soil. Feel free to add well-rotted compost at planting time. Finally, it dislikes chalky soil: it requires a neutral or acidic substrate.

Dianella will integrate easily into a Mediterranean or exotic-style garden. Varieties with brown foliage (like Dianella ‘Blaze’) or variegated leaves (Dianella tasmanica ‘Variegata’) are perfect for a graphic-style garden. Dianella can be planted in a raised rockery, ensuring ideal drainage, and will also create a stunning effect when planted along pathways. Taller varieties can be planted singly or in small groups, for example near the entrance of a house or along the edge of a short grass meadow to showcase their lush foliage, while smaller varieties, like Dianella ‘Little Rev’, will create a more striking effect when planted en masse.

When to Plant?

Plant Dianella in spring, in April or May, once the risk of frost has passed.

How to Plant?

In the ground:

1. Dig a planting hole, roughly twice the size of the root ball.
2. Refill it with soil mixed with well-rotted compost and add gravel or coarse sand if needed to improve drainage.
3. Remove the Dianella from its pot and place it in the planting hole.
4. Backfill with soil around the plant.
5. Water generously.
6. We recommend applying an organic mulch around the clump. This will help retain soil moisture longer, reducing the need for watering while also suppressing weed growth.

In a pot:

1. Choose a pot with drainage holes.
2. Place a layer of gravel or clay pebbles at the bottom.
3. Add a well-draining, non-chalky substrate. For example, create a mix with potting compost, garden soil, coarse sand, and optionally a bit of heather soil.
4. Remove the Dianella from its original pot and place it in the new one, centred well.
5. Add more compost around the root ball.
6. Water generously.

Place the pot in full sun or partial shade, sheltered from cold winds.

Dianella tasmanica

Maintenance

In the Ground

Water regularly in the weeks following planting to help the plant establish itself and develop its root system. If your water is hard, use rainwater if possible. Once established, Dianella tolerates summer drought well and can go without watering. However, you can apply a layer of mulch around the clump to keep the soil moist for longer.

Don’t hesitate to protect Dianella from the cold in winter by wrapping it in a winter fleece and spreading a thick layer of mulch around the clump.

Avoid cutting back faded inflorescences, or your Dianella won’t produce berries! After pollination, the flowers can give way to stunning metallic blue berries.

Dianella is not particularly susceptible to diseases or pests.

In Pots

In cooler regions, grow Dianella in pots and bring it under cover in autumn. Place it in a bright but not too warm spot, such as a conservatory or unheated greenhouse. You can move it back outdoors the following spring, once the risk of frost has passed.

If growing Dianella in pots, remember to water it regularly (once or twice a week) in spring and summer. You can reduce watering in autumn and winter. Preferably use rainwater. Avoid letting water stagnate in the saucer. We also recommend applying a little fertiliser to support growth and flowering. For example, use a liquid fertiliser, diluted in the watering water.

Multiplication

Sowing

To sow, you can pick the blue berries when they are fully ripe and then extract the seeds they contain. Germination appears to be aided by soaking the seeds in water for 24 hours.

1. Prepare pots by filling them with special sowing compost.
2. Lightly firm and level the surface of the compost.
3. Sow the seeds.
4. Cover with a thin layer of compost.
5. Water gently with a fine spray.
6. Place the pots in a sheltered, bright location, away from direct sunlight, ideally at a temperature between 13 and 16 °C. Temperatures above 18 °C may inhibit germination.

Ensure the substrate remains slightly moist until germination, which usually occurs after 2 weeks but may take longer. You can transplant the seedlings into individual pots once they reach a size that allows for easy handling. Wait until the following spring before planting them in the garden.

Division of Clumps

Dianella is a perennial with a rootstock, making it easy to divide. Compared to sowing, division allows you to obtain new young plants ready for the garden more quickly and simply. We recommend doing this in spring.

1. Choose a healthy, well-developed Dianella clump and carefully dig it up by excavating around it.
2. Remove excess soil if necessary to expose the roots and rootstock.
3. Divide the clump into several sections by cutting the rootstock. Ensure each fragment retains roots.
4. Replant in a new location after preparing the soil, or in pots.
5. Water generously.

Association

As it is particularly suited to mild coastal climates, you can incorporate Dianella into a Mediterranean-style garden. It will be perfect at the foot of the majestic silhouette of an olive tree, with dark-leaved varieties like Dianella ‘Blaze’ creating a stunning contrast with its silvery-grey foliage. Also consider rockroses, strawberry trees, fig trees, palms, and oleanders! Add aromatic herbs, such as lavenders, thymes, rosemaries, santolinas, and helichrysums. Introduce colour with the flowering of Phlomis fruticosa, agapanthus, Delosperma, and helianthemums.

Dianella blends effortlessly into a Mediterranean-style garden. Here, Agapanthus ‘Royal Velvet’, Dianella tasmanica (photo Adobe Stock), Nerium oleander ‘Emilie’, Agave americana ‘Variegata’, Helianthemum ‘Ben Fhada’, and Lavandula angustifolia ‘Hidcote’

Native to the Southern Hemisphere, particularly Australia, Dianella will naturally find its place in an exotic garden. Don’t hesitate to pair it with Australasian plants! Consider, for example, the striking foliage of Phormiums, Cordyline australis, and Carex comans ‘Bronze Form’. These foliage plants will create a stunning backdrop to highlight the flowering of Dietes bicolor, kniphofias, crocosmias, eucomis, and the highly original Anigozanthos. Also discover Tigridia pavonia, nicknamed Peacock Eye, a lovely bulb that produces white, yellow, or red flowers in summer, with a triangular corolla and a throat striped in purple.

Explore our inspiration page “Australian Exoticism”

Dianella helps create a beautiful “Australian Exoticism” atmosphere in the garden. Crocosmia ‘Sunglow’, Dianella longifolia (photo Adobe Stock), Kniphofia ‘Fiery Fred’, Eucomis ‘Sparkling Rosy’, Anigozanthos, and Phormium ‘Pink Panther’

The Dianella tasmanica ‘Blaze’ and ‘Variegata’, with their chocolate-brown or white-variegated foliage, are perfect for a graphic and contemporary garden. Design a garden with clean lines, well-defined borders, stepping-stone pathways, and pruned bushes (boxwood, Ilex crenata, Lonicera nitida…). We recommend opting for understated and elegant tones rather than bright colours: focus on white, purple, black, and bronze… Enjoy the highly graphic flowering of Allium schubertii, Echinops ‘Star Frost’, and agapanthus ‘Black Magic’ or ‘Glacier Stream’. You can also incorporate some ornamental grasses, such as Pennisetums or Stipas: their fine foliage and light spikes will add a lovely contrast.

You can also pair Dianella with other perennials and decorative fruit bushes. Consider, for example, callicarpa, symphoricarpos, euonymus, viburnums, Liriope muscari, and Maianthemum bifolium.